Semiconductor structure and manufacturing method thereof

ABSTRACT

A semiconductor structure is provided. The semiconductor structure includes a metallization structure with a dielectric surface. A first protecting structure over the dielectric surface. A first protecting structure over the passivation layer. A conductive pad over the dielectric surface. A polymer layer over the first protecting structure and the conductive pad. A conductive bump electrically coupled to the conductive pad through an opening of the polymer layer. A first portion of the first protecting structure is leveled with the conductive pad and a second portion of the first protecting structure is higher than the conductive pad.

CROSS REFERENCE TO RELATED APPLICATION

This continuation application claims the benefit of prior-filedapplication Ser. No. 16/425,538, filed May 29, 2019.

FIELD

The present disclosure is related to a semiconductor structure and, moreparticularly, to a semiconductor structure with a protecting structurebetween a metallization structure and a conductive bump.

BACKGROUND

Microelectronic semiconductor IC devices such as Complementary MetalOxide Semiconductor Field Effect Transistor (CMOS FET) devices and thelike are manufactured in a complex process in which numerous separateelectronic devices are formed. Such processes of manufacture, whichproduce large numbers of such electronic devices, are referred to asVery Large Scale Integration (VLSI) processes. After many processingsteps, conductive terminals such copper bumps and/or solder bumps are tobe disposed over interconnect structure during the Back End of Line(BEOL) process.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various structures are not drawn to scale. In fact, the dimensions ofthe various structures may be arbitrarily increased or reduced forclarity of discussion.

FIG. 1 illustrates a cross-sectional view of a semiconductor structureaccording to some embodiments of the present disclosure.

FIGS. 2A and 2B illustrate cross-sectional views of first protectingstructures according to some embodiments of the present disclosure.

FIGS. 3A to 3F illustrate cross-sectional views at various operations ofmanufacturing a semiconductor structure according to some embodiments ofthe present disclosure.

FIG. 3G illustrates a cross-sectional view of a semiconductor structureaccording to some embodiments of the present disclosure.

FIG. 4A illustrates a cross-sectional view of a semiconductor structureaccording to some embodiments of the present disclosure.

FIG. 4B illustrates a cross-sectional view of a semiconductor structureaccording to some embodiments of the present disclosure.

FIGS. 4C to 4J illustrate cross-sectional views at various operations ofmanufacturing a semiconductor structure according to some embodiments ofthe present disclosure.

FIGS. 5A and 5B illustrate cross-sectional views at various operationsof manufacturing a semiconductor structure according to some embodimentsof the present disclosure.

FIG. 6 illustrates a cross-sectional view of a semiconductor structureaccording to some embodiments of the present disclosure.

FIG. 7 illustrates a cross-sectional view of a semiconductor structureaccording to some embodiments of the present disclosure.

FIGS. 8A to 8F illustrate cross-sectional views at various operations ofmanufacturing a semiconductor structure according to some embodiments ofthe present disclosure.

FIGS. 9A and 9B illustrate cross-sectional views at various operationsof manufacturing a semiconductor structure according to some embodimentsof the present disclosure.

FIG. 10 illustrates a cross-sectional view of a third protectingstructure according to some embodiments of the present disclosure.

FIGS. 11A and 11B illustrate cross-sectional views at various operationsof manufacturing a semiconductor structure according to some embodimentsof the present disclosure.

FIG. 12 illustrates a cross-sectional view of a semiconductor structureaccording to some embodiments of the present disclosure.

FIG. 13 illustrates a cross-sectional view of a semiconductor structureaccording to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of elements and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper”, “on” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

As used herein, the terms such as “first”, “second” and “third” describevarious elements, components, regions, layers and/or sections, theseelements, components, regions, layers and/or sections should not belimited by these terms. These terms may be only used to distinguish oneelement, component, region, layer or section from another. The termssuch as “first”, “second”, and “third” when used herein do not imply asequence or order unless clearly indicated by the context.

Chip packaging interaction (CPI) may introduce mechanical stress tocomponents in the chip. Such interaction is between the semiconductorpackage and the semiconductor chip, and the stress generated in thepackage may be caused by thermal, mechanical and chemical mechanisms.For instance, when it is widely used to implement extreme low K (ELK)dielectric materials (k<2.5) into the BEOL of a semiconductor chip toreduce the interconnect capacitance and crosstalk noise and enhancecircuit performance, the lower mechanical strength of the layer, alongwith increased die size, difference in effective coefficient of thermalexpansion (CTE) between die and substrate, and the use of higherstiffness lead-free solder, all may bring the outcome of cracking at theELK layer. Also, the bonding pressure from the copper bump to thealuminum copper bonding pad may increase the stress suffered by thechip, and consequently, the structures inside the chip such aspassivation layers, metal-insulator-metal (MIM) structure, and ELKlayer, may be cracked and result in device failure.

Accordingly, CPI has become one of the critical reliability issuesduring the BEOL operations. Feasible approaches are required to preventthe underlying ELK layer, MIM structure, or even themetallization/interconnect structure in the chip from cracking byproviding an effective protecting structure to reduce the impact.

Mechanical stress may be induced by CPI and thus damage the chip due tothe bonding pressure delivered from the conductive bump to theconductive pad. Typically, the damage may be manifested as crackingwithin the chip at the structures fabricated during BEOL operations,especially the passivation layers, metal-insulator-metal (MIM) device,and extreme low K (ELK) layer below the conductive pad. In the presentdisclosure, as one of the embodiments shown in FIG. 1 , at least aprotecting structure is disposed on the dielectric surface of themetallization structure. Meanwhile, the protecting structure is leveledwith the conductive pad. Accordingly, the mechanical stress originatesfrom chip packaging interaction may be prevented from applying on thestructures or elements below the conductive pad.

As shown in FIG. 1 , the semiconductor structure of the presentdisclosure includes a metallization structure 100 having a dielectricsurface 101, a first protecting structure 103, a conductive pad 102, apolymer layer 104, and a conductive bump 109.

The metallization structure 100 includes a series of stacked layers overa substrate (e.g. silicon wafer). The stacked layers are fabricated toprovide individual devices (transistors, capacitors, resistors, etc.)get interconnected with metal wiring on the substrate. Accordingly,adjacent layers in the metallization structure 100 are linked togetherthrough the use of electrical contacts and vias. In some embodiments,the metallization structure 100 may be a multilayer structure includesan extreme low-k (ELK) dielectric layer 100 a, a via 100 b a metal line100 c laterally surrounded by a dielectric material 100 f, an etch-stoplayer 100 d, and a metal insulator metal (MIM) device 100 e stackedrespectively. The ELK dielectric layer 100 a may be a layer withdielectric constant (k) less than about 2.5, such as SiOC, SiOCN andSiCOH. In some embodiments, the MIM device 100 e is covered bydielectric material 100 f such as undoped silicate glass (USG) orfluorinated silicate glass (FSG) for enhanced structural stability. Theetch-stop layer 100 d may include the dielectric material such assilicon nitride, silicon dioxide, or carbon-doped silicon nitride. Insome embodiments, the metallization structure 100 is a back end of line(BEOL) structure or the devices thereof.

The conductive pad 102 is disposed on the dielectric surface 101 of themetallization structure 100. The conductive pad 102 may be made by anysuitable conductive material includes but not limited to metal (e.g.,copper, tantalum, titanium, molybdenum, tungsten, platinum, aluminum,hafnium, ruthenium), metal silicide (e.g., titanium silicide, cobaltsilicide, nickel silicide, tantalum silicide), or metal nitride (e.g.,titanium nitride, tantalum nitride). In some embodiments, the conductivepad 102 is formed by chemical vapor deposition (CVD), low pressurechemical vapor deposition, physical vapor deposition (PVD), atomic layerdeposition, or spin-on.

In some embodiments, the first protecting structure 103 is disposed onthe dielectric surface 101 and leveled with the conductive pad 102. Forexample, a bottom of the first protecting structure 103 and a bottom ofthe conductive pad 102 are disposed on the dielectric surface 101. Thefirst protecting structure 103 may be composed of silicon nitride orsilicon oxide with a thickness of from about 2,000 Å to about 3,000 Å.When the ELK dielectric material is disposed above and under the firstprotecting structure 103, an oxide-nitride-oxide (ONO) stack may beformed. Considering the lattice mismatch between oxide and nitride, theaforesaid thickness range of the first protecting structure 103 mayminimize the stress caused by lattice mismatch in ONO stack. In someembodiments, the first protecting structure 103 is formed by chemicalvapor deposition (CVD), plasma-enhanced CVD, spin-on, or otherapplicable methods. As shown in FIG. 2A, in some embodiments, the firstprotecting structure 103 is disposed on the dielectric surface 101 andthe conductive pad 102, and therefore the sidewalls 102 a and the topsurface 102 b of the conductive pad 102 are covered by the firstprotecting structure 103. In some embodiments, as shown in FIG. 2B,before forming the first protecting structure 103, the spacers 201 areformed on the sidewalls 102 a of the conductive pad 102. In someembodiments, the spacers 201 are made of silicon oxide, silicon nitride,silicon oxynitride, or other applicable material. In some embodiments,the spacers 201 are shaped by blanket-etching after disposed by chemicalvapor deposition (CVD), plasma enhanced CVD, sputter, spin-on, orphysical vapor deposition (PVD), or other applicable methods.

In consider the mechanical stress originated form chip packaginginteraction are mainly applied to the areas close to the conductivebump, in some embodiments, the present disclosure enhances the structurestrength of the peripheral areas of the conductive pad 102 by thespacers 201 and further resisting and dispersing the mechanical stressby the first protecting structure 103, and the mechanical stress exertedto the structures below the dielectric surface 101 may be reduced.

As shown in FIG. 3A, in some embodiments, a passivation layer 106 isdisposed on the first protecting structure 103 after forming thereof.The passivation layer 106 may be made of undoped silicate glass (USG),silicon oxynitride, phosphosilicate glass (PSG), borophosphosilicateglass (BPSG), fluorinated silicate glass (FSG), organosilicate glasses(OSG), SiOxCy, Spin-On-Glass, or the like. In some embodiments, thepassivation layer 106 is formed by high density plasma (HDP), chemicalvapor deposition (CVD), plasma enhanced CVD, sputter, spin-on, physicalvapor deposition (PVD), or other applicable methods. In someembodiments, the passivation layer 106 is made of USG with a thicknessof about 12000 Å to about 15000 Å.

As shown in FIG. 3B, in some embodiments, a second protecting structure105 is disposed on the passivation layer 106 after forming thereof, andtherefore the passivation layer 106 is disposed between the firstprotecting structure 103 and the second protecting structure 105. Thematerial of the second protecting structure 105 may be substantiallyidentical to the first protecting structure 103. Generally, in someembodiments, the second protecting structure 105 may be composed ofsilicon nitride or silicon oxide with a thickness of about 7000 Å. Insome embodiments, the second protecting structure 105 is formed bychemical vapor deposition (CVD), plasma-enhanced CVD, spin-on, or otherapplicable methods.

As shown in FIGS. 3C to 3F, and also refer to the previously addressedFIG. 1 , in some embodiments, a polymer layer 104 is disposed over thefirst protecting structure 103 and the conductive pad 102, and aconductive bump 109 is formed and electrically coupled to the conductivepad 102 through an opening 202 of the polymer layer 104 after formingthe second protecting structure 105. The polymer layer 104 is made bypolyimide with a thickness about 50,000 Å. The polymer layer 104 ispatterned by a mask and implemented with an etching operation to havethe opening 202 to expose a portion of the top surface of the conductivepad 102 for forming an under bump metallurgy (UBM) 108 thereon. Afterforming the UBM 108, the conductive bump 109 is formed on the UBM 108.In some embodiments, the conductive bump 109 includes a copper bumps 109a and a flat bump surface covered by a solder paste 109 b. The solderpaste 109 b may be further reflowed and attached to the contact pads ofother electrical components, for example, attached to a PCB.

Although the first protecting structure 103 is leveled with theconductive pad 102 in some embodiment, as shown in FIG. 3G, further insome embodiments, the edges of the first protecting structure 103 isheightened by the spacers 201 and thus in contact with the secondprotecting structure 105. Accordingly, the first protecting structure103 and the second protecting structure 105 may be integrated partiallyand resisting and dispersing the mechanical stress jointly.

In the present disclosure, the first protecting structure may not belimited to a generally flat layer. As shown in FIG. 4A, in someembodiments, the first protecting structure 103 may be divided into afirst portion 103 a and a second portion 103 b. The first portion 103 ais leveled with the conductive pad 102, whereas the second portion 103 bis higher than the conductive pad 102. In other words, the firstprotecting structure 103 may have a trench shaped structure and incontact with the dielectric surface 101 at the first portion 103 a. Insome embodiments, the first protecting structure 103 includes aplurality of trenches 103 c and each of the trenches 103 c are filled bythe polymer layer 104. Accordingly, the polymer layer 104 thus includesa plurality of polymer protrusions 104 a aligns to the same directionand forms a quasi-spring structure for absorbing mechanical stress.Moreover, because the polymer layer 104 is formed by polyimide which hasa Young's modulus of 2.5 GPa and it is more flexible than the firstportion 103 a and a second portion 103 b of the first protectingstructure 103, as well as the passivation layer 106 therebelow. Theportion of the polymer layer 104 extended into the trenches 103 c mayprovide further absorbing functions to reduce the mechanical stressdelivers to the structures below the dielectric surface 101.

Furthermore, in some embodiments, as shown in FIG. 4A, a width of thetrench W_(103c) is smaller than a depth of the trench D_(103c), thus notonly the density of the polymer protrusions 104 a is high, but also thecontacting area between the polymer layer 104 and the first protectingstructure 103 is large. By increasing the contacting area, themechanical stress originates from chip packaging interaction will beharder to be delivered to the structures below the first protectingstructure.

In some embodiments, as shown in FIG. 4B, the width of the trenchW_(103c) is larger than a depth of the trench D_(103c), the density ofthe polymer protrusions 104 a is less than previous embodiments but eachpolymer protrusion 104 a has more amount of polymer material andtherefore the polymer layer 104 may absorb more mechanical stressdelivers form the conductive bump 109 and protect the structurestherebelow.

The forming of the first protecting structure 103 includes variousoperations. As shown in FIGS. 4C and 4D, the passivation layer 106 isdisposed on the dielectric surface 101 and the conductive pad 102. Insome embodiments, the passivation layer 106 is made of undoped silicateglass (USG) under high density plasma (HDP) and with a thickness of fromabout 12,000 Å to 15,000 Å. Alternatively, other methods such aschemical vapor deposition (CVD), plasma-enhanced CVD, or spin-on arealso applicable. And then, a preliminary protecting structure 103 d isdisposed on the passivation layer 106. In some embodiments, thepreliminary protecting structure 103 d is formed by silicon nitride orsilicon oxide with a thickness of about 7000 Å. As shown in FIGS. 4E and4F, the preliminary protecting structure 103 d and the passivation layer106 are patterned by a mask 300 and implemented with an etchingoperation to have a plurality of openings 203 to expose a portion of thetop surface of the conductive pad 102 and a portion of the dielectricsurface 101. Generally, the bottoms of the openings 203 are not lowerthan the dielectric surface 101 to avoid damaging the metallizationstructure 100. As shown in FIG. 4G, by another deposition operation, thematerial of the protecting structure such as silicon nitride or siliconoxide are further disposed on the sidewalk and bottoms of the openings203, by integrating with the preliminary protecting structure 103 d, thefirst protecting structure 103 is therefore formed on the dielectricsurface 101 and cover the passivation layer 106 and the conductive pad102. In some embodiments, the thickness of the integrated firstprotecting structure 103 is no less than about 7,000 Å.

As shown in FIGS. 4H to 4J, in some embodiments, the polymer layer 104is disposed on the first protecting structure 103 and over thepassivation layer 106 and the conductive pad 102. The polymer layer 104is made by polyimide with a thickness about 50,000 Å. The polymer layer104 is patterned by a mask 301 and implemented with an etching operationto have the opening 204 to expose a portion of the top surface of theconductive pad 102 for forming the under bump metallurgy (UBM) thereon.Accordingly, in some embodiments, the second protecting structure aspreviously shown in FIG. 3G may not be disposed independently from thefirst protecting structure, instead, the second protecting structure maybe integrated with the first protecting structure in certaincircumstances. For instance, in the case of the protecting structureincluding a periodic change of pattern below the polymer layer.

In some embodiments, the first protecting structure 103 in FIG. 4G maybe formed directly by fewer operations instead of forming thepreliminary protecting structure 103 d in advance as shown in FIGS. 4Dto 4F. For illustration, as shown in FIGS. 5A and 5B, after forming thepassivation layer 106 on the dielectric surface 101 and the conductivepad 102, the passivation layer 106 is patterned by a mask 302 andimplemented with an etching operation to have a plurality ofopenings/trenches 205 to expose a portion of the top surface of theconductive pad 102 and a portion of the dielectric surface 101. Next,the first protecting structure 103 is disposed on the passivation layer106 and the exposed conductive pad 102, and therefore covers thesidewalls of the openings/trenches 205. In some embodiments, the firstprotecting structure 103 may be formed in a single deposition operation,whereas in some other embodiments, it may be formed in separateddeposition operations. The different approaches with differentoperations may be selected depends on the convenience of process, forinstance, to comply with standard logic process.

In some embodiments, as shown in FIG. 6 , the first protecting structure103 is disposed on the passivation layer 106 with a trench shapedstructure having a plurality of turns that changes periodically alongthe upper surface of the passivation layer 106. The bottom surface ofthe first protecting structure 103 may be raised from the dielectricsurface 101. In other words, in some embodiments, the position of thefirst protecting structure 103 depends on the structure of thepassivation layer 106. In some embodiments, the passivation layer 106includes a plurality of protrusions 106 a higher than the conductive pad102. Accordingly, when the protrusions 106 a are on the dielectricsurface 101 with a common base 106 b in some embodiments, the firstprotecting structure 103 is thus raised from the dielectric surface 101;and when the protrusions 106 a are on the dielectric surface 101 withoutthe common base 106 b, the first protecting structure 103 may in contactwith the dielectric surface 101. Furthermore, in some embodiments, theheight of the common base 106 b is less than the height of theconductive pad 102, and the bottom of the first portion 103 a of thefirst protecting structure 103 is lower than the top surface of theconductive pad 102.

In some embodiment, the height of the protrusions 106 a may be identicalto the height of the conductive pad 102. In some embodiments, theprotrusions 106 a cover the sidewalls of the conductive pad 102. Referto the previously addressed FIG. 1 , in some embodiments, theprotrusions can be the spacers 201.

Comparing to the embodiments as shown in previously addressed FIG. 3G,in some embodiments, the first protecting structure 103 is not onlydisposed on the dielectric surface 101 of the metallization structure100 and leveled with the conductive pad 102, but also laterallysurrounded by the passivation layer 106. In other words, in someembodiments as shown in FIG. 7, the first protecting structure 103covers a portion of the dielectric surface 101 and the exposeddielectric surface 101 may further be covered by the passivation layer106. In FIG. 7 , the first protecting structure 103 can be a dummyconductive pad leveled with the conductive pad 102 receiving theconductive bump 109 a. The dummy conductive pad may not be electricallycoupled to any component in the chip.

As shown in FIG. 8A, in some embodiments, the first protecting structure103 is disposed on the dielectric surface 101, the material of the firstprotecting structure 103 may be identical to the conductive pad 102. Insome embodiments, the first protecting structure 103 may be formed bysilicon nitride or silicon oxide whereas the conductive pad 102 isformed by any suitable conductive material includes but not limited tometal (e.g., copper, tantalum, titanium, molybdenum, tungsten, platinum,aluminum, hafnium, ruthenium), metal silicide (e.g., titanium silicide,cobalt silicide, nickel silicide, tantalum silicide), or metal nitride(e.g., titanium nitride, tantalum nitride). Hence, the conductive pad102 and the first protecting structure 103 are formed in differentoperations due to different materials. However, in some embodiments, thematerial of the first protecting structure 103 and the material of theconductive pad 102 are substantially identical. Namely, the firstprotecting structure 103 is also formed by any suitable conductivematerial includes but not limited to metal, metal silicide, or metalnitride. In some embodiments, both of the conductive pad 102 and thefirst protecting structure 103 are formed simultaneously by chemicalvapor deposition (CVD), low pressure chemical vapor deposition, physicalvapor deposition (PVD), atomic layer deposition, or spin-on. In someembodiment, the first protecting structure 103 is a dummy pad.

In some embodiment, the top surface of the first protecting structure103 is aligned with the top surface of the conductive pad 102. In someembodiments, the thickness of the first protecting structure 103 isabout 25,000 Å to 30,000 Å.

As shown in FIG. 8B, in some embodiment, after forming the conductivepad 102 and the first protecting structure 103 on the dielectric surface101, the passivation layer 106 is disposed by plasma enhanced oxidedeposition (PEOX) and covers the exposed dielectric surface 101, theconductive pad 102 and the first protecting structure 103. In someembodiments, the thickness of the passivation layer 106 is about 12,000Å. Then, the preliminary protecting structure 105 a is disposed on thepassivation layer 106. In some embodiments, the thickness of thepreliminary protecting structure 105 a is about 7,000 Å.

As shown in FIGS. 8C and 8D, the passivation layer 106 and thepreliminary protecting structure 105 a are patterned by a mask 303 andimplemented with an etching operation to have an opening 206 to expose aportion of the top surface of the conductive pad 102. Afterwards, insome embodiments, as shown in FIG. 8E, the material of the protectingstructure such as silicon nitride or silicon oxide are further disposedon the preliminary protecting structure 105 a and the sidewall andbottom of the openings 206, by integrating with the preliminaryprotecting structure 105 a, the second protecting structure 105 istherefore formed on the passivation layer 106 and the conductive pad102. In some embodiments, the thickness of the material of theprotecting structure disposed posterior to the forming of the secondprotecting structure 105 is about 2,000 Å to 5,000 Å.

In addition, in some embodiments, as shown in FIG. 8F, a thirdprotecting structure 110 may be disposed on the second protectingstructure 105. The material of the third protecting structure 110 may beany suitable conductive material includes but not limited to metal,metal silicide, or metal nitride. In some embodiments, the material ofthe third protecting structure 110 and the material of the conductivepad 102 are substantially identical. In some embodiments, the materialof the first protecting structure 103, the third protecting structure110, and the conductive pad 102 are substantially identical. In someembodiments, the thickness of the third protecting structure 110 isabout 2000 Å to 5000 Å. By using the third protecting structure 110, themechanical stress from chip packaging interaction may be releasedhorizontally to the areas distant to the conductive bump 109, so thatthere is less mechanical stress be delivered vertically or obliquely tothe metallization structure and damage the layers thereof.

In some embodiments, the second protecting structure 105 in FIG. 8E maybe formed directly by less operations instead of forming the preliminaryprotecting structure 105 a in advance as shown in FIGS. 8B to 8D. Asshown in FIGS. 9A and 9B, after forming the passivation layer 106 on thefirst protecting structure 103, the dielectric surface 101, and theconductive pad 102, the passivation layer 106 is patterned by a mask 304and implemented with an etching operation to have an openings 207 toexpose a portion of the top surface of the conductive pad 102. Next, thesecond protecting structure (not shown) may be disposed on thepassivation layer 106 and the exposed conductive pad 102, and alsocovers the sidewalls of the openings 207. Accordingly, in someembodiments, the second protecting structure may be formed in a singledeposition operation, whereas in some other embodiments, it may beformed in separated deposition operations. The different approaches withdifferent operations may be selected depends on the convenience ofprocess, for instance, to comply with standard logic process.

As shown in FIG. 10 and the previously presented FIG. 8E, in someembodiments, the second protecting structure 105 may not be disposedafter forming the passivation layer 106, instead, only the thirdprotecting structure 110 is disposed on the passivation layer 106. Insuch embodiment, the third protecting structure 110 is made by metal,metal silicide, or metal nitride instead of silicon nitride or siliconoxide. It is considered that the ductility of metal material may providebetter performance in resisting and dispersing the mechanical stressthan silicon nitride and silicon oxide.

As shown in FIGS. 11A, 11B, and 12 , in some embodiments, after theforming the third protecting structure 110, the polymer layer 104 isdisposed thereon. In some embodiments, the polymer layer 104 is made bypolyimide with a thickness about 50,000 Å. Then, the polymer layer 104is patterned by a mask 305 and implemented with an etching operation tohave the opening 208 to expose a portion of the top surface of theconductive pad 102 for forming an under bump metallurgy (UBM) 108thereon. After forming the UBM 108, the conductive bump 109 is formed onthe UBM 108. In some embodiments, the conductive bump 109 includes thecopper bump 109 a and the flat bump surface covered by the solder paste109 b. The solder paste 109 b may be further reflowed and attached tothe contact pads of other electrical components.

As shown in FIG. 13 , in some embodiments, the conductive pad 102 iselongated to protect the layers therebelow. In some embodiments, thewidth of the conductive pad 102 is larger than the width of the copperbump 109 a measured above the surface of the polymer layer 104.Furthermore, in some embodiments, not only the conductive pad 102 iselongated, but also the amount of the polymer below the conductive bump109 is increased. By having an elongated conductive pad, in someembodiments, the polymer layer 104 includes at least a thickeningportion 104 b between the second protecting structure 105 and the underbump metallurgy (UBM) 108 over the conductive pad 102, and a horizontalwidth W_(104b) of the thickening portion 104 b is larger than a verticalheight H_(104b) thereof. In some embodiments, the horizontal widthW_(104b) of the thickening portion 104 b is larger than 50,000 Å. Thethickening portions 104 b may perform as buffer structures to absorb themechanical stress form the conductive bump 109. Especially the positionsof the thickening portions 104 b are close to the position where themechanical stress occurs and the cracks originates, which are criticalin solving the cracking issue raised by chip packaging interaction.

In the present disclosure, the semiconductor structure includes at leasta protecting structure disposed on the dielectric surface of themetallization structure and leveled with the conductive pad. And theprotecting structure may cover the dielectric surface entirely orpartially among different embodiments. Also, the protecting structuremay be a generally flat layer or a trench shaped structure amongdifferent embodiments and cooperate with the shape of the polymer layerthereabove. Furthermore, the protecting structure may be separated intodivided layers and disposed between the under bump metallurgy and themetallization structure.

In one exemplary aspect, a semiconductor structure is provided. Thesemiconductor structure includes: a metallization structure, a firstprotecting structure, a conductive pad, a polymer layer, and aconductive bump. The metallization structure has a dielectric surface.The first protecting structure is on the dielectric surface. Theconductive pad is on the dielectric surface and is leveled with thefirst protecting structure. The polymer layer is over the firstprotecting structure and the conductive pad. The conductive bump iselectrically coupled to the conductive pad through an opening of thepolymer layer.

In another exemplary aspect, a semiconductor structure is provided. Thesemiconductor structure includes: a metallization structure, aconductive pad, a passivation layer, and a protecting structure. Themetallization structure has a dielectric surface. The conductive pad ison the dielectric surface. The passivation layer is on the dielectricsurface and has a plurality of protrusion structures. The protectingstructure covers the passivation layer.

In yet another exemplary aspect, a method for manufacturing asemiconductor structure is provided. The method includes the followingoperations. A metallization structure having a dielectric surface isprovided. A conductive pad is formed on the dielectric surface. A firstprotecting structure is formed on the dielectric surface and be leveledwith the conductive pad. A polymer layer is formed over the firstprotecting structure and the conductive pad.

The foregoing outlines structures of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A semiconductor structure, comprising: ametallization structure having a dielectric surface; a passivation layerover the dielectric surface; a first protecting structure over thepassivation layer; a conductive pad over the dielectric surface; apolymer layer over the first protecting structure and the conductivepad; and a conductive bump electrically coupled to the conductive padthrough an opening of the polymer layer; wherein a first portion of thefirst protecting structure is leveled with the conductive pad and asecond portion of the first protecting structure is higher than theconductive pad; and wherein the first protecting structure furthercomprises a plurality of trenches filled by the polymer layer.
 2. Thesemiconductor structure of claim 1, wherein a width of the trench issmaller than a depth of the trench.
 3. The semiconductor structure ofclaim 1, wherein the passivation layer comprises undoped silicate glass(USG).
 4. The semiconductor structure of claim 1, wherein a thickness ofthe passivation layer is in a range of from about 12,000 Å to about15,000 Å.
 5. The semiconductor structure of claim 1, wherein the firstprotecting structure comprises silicon nitride or silicon oxide.
 6. Thesemiconductor structure of claim 1, wherein the polymer layer comprisespolyimide.
 7. A semiconductor structure, comprising: a metallizationstructure having a dielectric surface; a passivation layer over thedielectric surface; a first protecting structure having a first portionin contact with the dielectric surface and a second portion over thepassivation layer; a conductive pad over the dielectric surface; apolymer layer over the first protecting structure and the conductivepad; and a conductive bump electrically coupled to the conductive padthrough an opening of the polymer layer; wherein the first protectingstructure further comprises a plurality of trenches filled by thepolymer layer.
 8. The semiconductor structure of claim 1, wherein asidewall of the conductive pad is in contact with the passivation layer.9. The semiconductor structure of claim 1, wherein a sidewall of theconductive pad is free from in contact with the first protectingstructure.
 10. The semiconductor structure of claim 1, wherein theconductive bump comprises copper bump in contact with the conductivepad.
 11. The semiconductor structure of claim 7, wherein a width of thetrench is larger than a depth of the trench.
 12. The semiconductorstructure of claim 7, wherein the passivation layer comprises undopedsilicate glass (USG).
 13. The semiconductor structure of claim 7,wherein a thickness of the passivation layer is in a range of from about12,000 Å to about 15,000 Å.
 14. The semiconductor structure of claim 7,wherein the first protecting structure comprises silicon nitride orsilicon oxide.
 15. The semiconductor structure of claim 7, wherein athickness of the polymer layer is about 50,000 Å.
 16. A semiconductorstructure, comprising: a metallization structure having a dielectricsurface; a passivation layer over the dielectric surface; a firstprotecting structure over the passivation layer, the first protectingstructure has a plurality of turns that changes periodically along anupper surface of the passivation layer; a conductive pad over thedielectric surface; a polymer layer over the first protecting structureand the conductive pad; and a conductive bump electrically coupled tothe conductive pad through an opening of the polymer layer; wherein thefirst protecting structure further has a plurality of trenches filled bythe polymer layer.
 17. The semiconductor structure of claim 16, whereinthe passivation layer has a common base and a plurality of protrusionsover the common base.
 18. The semiconductor structure of claim 17,wherein a top surface of each of the plurality of protrusions of thepassivation layer is higher than a top surface of the conductive pad.19. The semiconductor structure of claim 17, wherein a height of thecommon base is less than a height of the conductive pad.
 20. Thesemiconductor structure of claim 16, wherein a bottom of the firstprotecting structure is lower than a top surface of the conductive pad.